GPT-5.1 variant optimized for agentic coding in Codex-style harnesses. Tuned for long tool-use loops, code editing, and repository-scale tasks, and served via the OpenAI Responses API.
Test this model instantly in the Console Playground โ no code required
Copy usage instructions for Claude, ChatGPT, or other AI
| Token Type | Credits | USD Equivalent |
|---|---|---|
| Input Tokens | 2,322.5 | $1.55 |
| Output Tokens | 18,580 | $12.39 |
| Cached Tokens | 232.25 | $0.15 |
* 1,500 credits โ $1 (actual charges may vary based on usage)
curl -X POST "https://api.core.today/llm/openai/v1/responses" \
-H "Content-Type: application/json" \
-H "Authorization: Bearer cdt_your_api_key" \
-d '{
"model": "gpt-5.1-codex",
"input": "Refactor this function to remove the duplicated error handling, and add a unit test:\n\n<code snippet>",
"max_output_tokens": 4000
}'| Parameter | Type | Required | Default | Description |
|---|---|---|---|---|
model | string | Yes | gpt-5.1-codex | Model identifier |
input | string | array | Yes | - | Responses API input: a plain string or an array of input items (messages, tool results) |
instructions | string | No | - | System-level instructions for the run |
max_output_tokens | integer | No | - | Maximum tokens in the response (Responses API field; not max_tokens) |
stream | boolean | No | false | Enable Server-Sent Events streaming |
Responses API request for a coding task
curl -X POST "https://api.core.today/llm/openai/v1/responses" \
-H "Content-Type: application/json" \
-H "Authorization: Bearer cdt_your_api_key" \
-d '{
"model": "gpt-5.1-codex",
"input": "Refactor this function to remove the duplicated error handling, and add a unit test:\n\n<code snippet>",
"max_output_tokens": 4000
}'POST /llm/openai/v1/responses